The Origin of Malarial Parasites in Orangutans

Authors

M. Andreína Pacheco, Arizona State University
Michael J.C. Reid, University of Toronto
Michael A. Schillaci, University of Toronto Scarborough
Carl A. Lowenberger, Simon Fraser University
Biruté M. F. Galdikas, Simon Fraser University
Lisa Jones-Engel, University of Washington
Ananias A. Escalante, Arizona State UniversityFollow

ORCID IDs

Escalante 0000-0002-1532-3430

Document Type

Article

Date of this Version

3-8-2012

Citation

PLoS One (2012) 7(4): e34990

doi: 10.1371/journal.pone.0034990

Comments

Open access

License: CC BY

Abstract

Background: Recent findings of Plasmodium in African apes have changed our perspectives on the evolution of malarial parasites in hominids. However, phylogenetic analyses of primate malarias are still missing information from Southeast Asian apes. In this study, we report molecular data for a malaria parasite lineage found in orangutans.

Methodology/Principal Findings: We screened twenty-four blood samples from Pongo pygmaeus (Kalimantan, Indonesia) for Plasmodium parasites by PCR. For all the malaria positive orangutan samples, parasite mitochondrial genomes (mtDNA) and two antigens: merozoite surface protein 1 42 kDa (MSP-1₄₂) and circumsporozoite protein gene (CSP) were amplified, cloned, and sequenced. Fifteen orangutans tested positive and yielded 5 distinct mitochondrial haplotypes not previously found. The haplotypes detected exhibited low genetic divergence among them, indicating that they belong to one species. We report phylogenetic analyses using mitochondrial genomes, MSP-1₄₂ and CSP. We found that the orangutan malaria parasite lineage was part of a monophyletic group that includes all the known non-human primate malaria parasites found in Southeast Asia; specifically, it shares a recent common ancestor with P. inui (a macaque parasite) and P. hylobati (a gibbon parasite) suggesting that this lineage originated as a result of a host switch. The genetic diversity of MSP-1₄₂ in orangutans seems to be under negative selection. This result is similar to previous findings in non-human primate malarias closely related to P. vivax. As has been previously observed in the other Plasmodium species found in non-human primates, the CSP shows high polymorphism in the number of repeats. However, it has clearly distinctive motifs from those previously found in other malarial parasites.

Conclusion: The evidence available from Asian apes indicates that these parasites originated independently from those found in Africa, likely as the result of host switches from other non-human primates.